Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 56 for “"delta sigma"”.
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Circuit level synthesis for delta-sigma converters
… a discrete-time, one-bit, oversampling delta-sigma analog-to-digital modulator circuit synthesis tool in MATLAB script. With the parameters of center frequency, loop order, oversampling ratio, and minimum capacitor size, a user can utilize the program to generate a semi-optimized …
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ALL-OPTICAL DELTA-SIGMA MODULATOR DESIGN AND IMPLEMENTATION
… an approach to design and implement all-optical delta-sigma modulator (ODSM) has been expanded. The two main blocks of this modulator are “leaky integrator” and “bi-stable switch” designed and implemented by using active element like semiconductor optical amplifier (SOA) and other passive …
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Continuous-Time Delta-Sigma Modulators for Wireless Communication
… papers that focus on the continuous-time (CT) Delta-Sigma modulator (DSM) as ADC. Paper I analyses the performance degradation of dynamic nonlinearity in the feedback DAC of the DSM, caused by Vth mismatch in the current-switching (differential) pair of a current-steering DAC. A model is …
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A Comparator-Based Switched-Capacitor delta sigma modulator
… applied to an industrial standard second order delta-sigma modulator originally based on op-amps. Due to the differences between CBSC and op-amp, a few architectural changes are necessary for the original modulator. Finally, the performance of transistor level simulation of this CBSC based …
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Design of a continuous-time bandpass delta-sigma modulator
An 8th-order continuous-time (CT) bandpass delta-sigma modulator has been designed and simulated in a 65 nm CMOS process. This modulator achieves in simulation 25 MHz signal bandwidth at 250 MHz center frequency with a signal-to- noise ratio (SNR) of 75.5 dB. The modulator samples at 1 GS/s while …
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A subsampling delta-sigma modulator for global navigation satellite systems
… the signals of interest. Continuous-Time (CT) Delta-Sigma (ΔΣ) modulation is an attractive candidate for subsampling Analog-to-Digital (A/D) conversion as it provides noise-shaping and inherent Anti-Alias (AA) filtering. However, the attenuation of the RF alias in the feedback path of the …
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Continuous-Time Delta-Sigma Modulators for Ultra-Low-Power Radios
… an ADC, but in the last decade, continuous-time Delta-Sigma modulators (CT DSMs) have become popular due to their potential of achieving low power consumption and the inherent anti-alias filtering. This thesis investigates different implementations of CT DSMs intended for an ultra-low-power (ULP) …
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An Exploratory Study of Pulse Width and Delta Sigma Modulators
… noise shaping and noise producing qualities of Delta-Sigma Modulators (DSM) and Pulse-Width Modulators (PWM). DSM has long been dominant in the Delta Sigma Analog-to-Digital Converter (DSADC) as a noise-shaped quantizer and time discretizer, while PWM, with a similar self oscillating structure, …
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Delta-Sigma digital-RF modulation for high data rate transmitters
… power, wideband wireless transmitter utilizing [Delta]-[Sigma] direct digital modulation of an RF carrier is presented. The transmitter architecture replaces high dynamic range analog circuits with high speed digital circuits and a passive LC bandpass filter, saving power and area compared to …
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Comparison of two bandpass delta-sigma A/D converter architectures
Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.
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DESIGN AND PERFORMANCE ANALYSIS OF AN OPTICAL PROTERETIC DELTA-SIGMA MODULATOR
… toward developing all-optical binary delta sigma modulator (BDSM) [27] by changing its bistability to proteretic bistability in order to increase the modulator bandwidth frequency. An innovative delta sigma modulator called proteretic binary delta sigma modulator (PBDSM), which is …
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Design techniques for Power-Efficient Delta-Sigma Analogue-to-Digital Converters
… from recent publications. This is a feed-forward Delta-Sigma Modulator (DSM), hybridised with a Successive Approximation Register (SAR) ADC as a quantiser, which also takes the role of a summing node, to further reduce the power consumption. A continuous-time amplification front-end is added …
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Multi-Bit Delta -Sigma Modulation Technique for Fractional-N Frequency Synthesizers
This thesis proposes a multi-bit Delta-Sigma modulation technique as a spur reduction method to enhance the overall synthesizer performance, and the oversampling modulator performance is analyzed with the consideration of practical design aspects for frequency synthesizers. A prototype fractional- …
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THEORETICAL INVESTIGATION AND PERFORMANCE ASSESSMENT OF REVERSED HYSTERESIS DELTA SIGMA MODULATOR DESIGN
This dissertation studies a unique delta sigma modulator (DSM), known as reversed hysteresis delta sigma modulator (R-HDSM). This modulator is appropriate for ultra-high speed analog-to-digital converters, which can be used for communications and signal processing systems and their applications. …
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Dynamic Element Matching Techniques For Delta-Sigma ADCs With Large Internal Quantizers
… enable high internal quantizer resolution in delta-sigma analog-to-digital converters. Increasing the quantizer resolution in a delta-sigma modulator can increase SNR, improve stability and reduce integrator power consumption. However, each added bit of quantizer resolution also causes an …
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Successive-approximation-register based quantizer design for high-speed delta-sigma modulators
High-speed delta-sigma modulators are in high demand for applications such as wire-line and wireless communications, medical imaging, RF receivers and high-definition video processing. A high-speed delta-sigma modulator requires that all components of the delta-sigma loop operate at the desired …
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A low-voltage zero-crossing-based delta-sigma analog-to-digital converter
… was used to design a single-bit 4th-order delta-sigma analog-to-digital converter for audio applications. The prototype ADC was implemented in 0.13 [mu]m CMOS and achieves 11.9 ENOB for 60 kHz input bandwidth while dissipating 1.2 mW power.
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Theory and applications of delta-sigma analogue-to-digital converters without negative feedback
… the main goal of this thesis is to develop sigma-delta data converters without feedback. Various new delta-sigma analog-to-digital converter topologies are explored their mathematical models are presented. Simulations are carried out to validate these models and to show performance results. …
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A continuous-time multi-stage noise-shaping delta-sigma modulator with analog delay
A new continuous-time multi-stage noise-shaping delta-sigma modulator has been designed. This modulator provides high resolution and robust stability characteristics which are the primary advantages of the conventional multi-stage noise-shaping architecture. At the same time, previous critical …
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